1. Field of the Invention
The present invention relates to an information recording medium, a manufacturing method of its recording medium, an information process unit and a copyright management system. More particularly, the invention is applied to a field of copyright protection technology for reading and writing digital AV information by using information individual to a magnetic disk medium and non-rewritable, and further the invention is capable of recording and reproducing copyrighted digital AV information while securely protecting the copyright.
2. Description of the Related Art
Conventionally, an information recording medium for a computer is required to copy digital information correctly, where it is recorded and regenerated as the same digital information no matter how many times it is repeatedly copied or even if it is copied on another recording medium.
While digital AV information can be obtained from the information record media such as the Internet, a digital broadcast and a DVD, it can be copied once accumulated as the digital information and then the copyright thereof can no longer be protected. Although there are copy protection technologies and so on, copying becomes possible, in the case of copy control information for instance, just by deleting or rewriting this information. This is ascribable to the fact that a magnetic disk unit mainly used as an external storage of the computer is capable of reading and rewriting all the data according to an instruction from the computer. The magnetic disk unit freely allows all recorded data to be read and written in order to securely store programs and data of the computer.
(Problems in the Prior Art)
(Problem 1)
In recent years, however, the act of copying itself leads to infringement of the copyright in the case of the copyrighted digital information such as the digital AV information (Audio-Visual information).
Currently, the information recording medium such as the DVD embedded with a scramble code that cannot be regenerated without descrambling copyright protection is not perfect because a hacker or the like creates a program and so on for releasing the protection.
Thus, there is a first problem that the copyright protection is not perfect as to the information recording medium itself such as a magnetic disk medium.
(Problem 2)
Consequently, a digital record system incorporating the copyright protection is now required apart from the record system used on the computers so far. In particular, a digital broadcast and so on must receive special attention because, as the same radio wave is received by all the receivers, individually different encryption is difficult and then the digital AV information may be copied and illegally used if once decrypted.
Here, it will be described more concretely.
As for the copyrighted digital AV information, a function of freely allowing reading and writing of all the data recorded on the information recording medium is very dangerous, where it is possible to analyze the digital AV information and an unprotect key by rewriting the program of the computer. Once the digital AV information is thereby decrypted, there is a fear that the digital AV information leaks all over the world through the Internet and so on. It has been impossible to completely prevent it since control by programming is possible in the range of an interface with the computer.
For that reason, in order to handle the copyrighted digital AV information, it is necessary to add a function different from the conventional magnetic disk unit capable of reading and rewriting all the data recorded on the information recording medium based on an instruction from the computer.
In addition, there are the cases where the copyright protection is implemented by using an encryption process, yet it is possible to unprotect the copyright relatively easily by a technique performing directly analyzing with a logic analyzer or the like an interface route between the computer and a recording apparatus or a signal line with the Internet connecting the computer to an external server or by a technique providing a pseudo signal looking as if authenticated. In particular, the unprotect key or encryption key is smaller in capacity than the encrypted digital AV information, and so it is easy to directly read or rewrite the content of the information. In the case where it is cracked, the digital AV information is decrypted and is no longer secure however advanced the performed encryption is.
Thus, there is a second problem that it is not possible to record and regenerate the copyrighted digital AV information while securely protecting the copyright.